Research efforts during the next budget year will be divided between biosynthesis and biogenetic-type synthesis of polycyclic natural products of polyketide origin. The synthetic efforts will be centered upon development of new methods for synthesis of polycarbonyl compounds. In particular, the development of convergent synthetic approaches and the use of selected protection will be stressed. Biosynthetic studies will involve completion of a detailed study of griseofulvin and initiation of new studies using 1,2-13C acetate. This reagent can provide information about cyclizations of polyketide chains which is not readily extracted from experiments using singly labelled precursors.